(Bach) says:"At all events, it is our custom to believe the man’s claims and even to marry him to a Jewess." Then Joel Sirkes proceeds to explain away partially the objections of Maimonides against believing the man. Joel Sirkes ' statement is cited with approval by Sabbatai Cohen(Shakh, to Shulhan Arukh, Yoreh Deah 368:10 and 11). Sirkes to the Tur also quotes the well-known legal authority Moses, of Coucy, in his SMag, who says:"This occurs every day. Strangers come(and claim to be Jews ). We do not bother to investigate. We drink wine with them and eat meat from their slaughtering." This general tendency of the law to accept the claim of a man that he is a Jew is reflected in a recent responsum by Isaac ben Aryeh Rudnik(S’dei Yitzhaq, London , 1961). The case with which he deals is that of a soldier who came to England from overseas, who claimed to be a Jew , married a Jewess; then his wife left him and lived with another man. Rabbi Rudnik decides that the marriage to the soldier who said he was a Jew is valid enough as Jewish marriage to require a Jewish divorce(get).
Of course, all this discussion involves the claimed conversion of a man. Our case here involves a woman whose conversion to Judaism is disputed. Nevertheless, the Shulhan Arukh understands that the above laws apply equally to man and woman. It cites the Talmudic law as follows(Yoreh Deah 268:10):"If a Gentile man or a Gentile woman come and say,‘1 have been converted'...," and so forth. The spirit of the law is clear. It reveals a growing tendency to accept the claim of a person or a family to be Jewish . Furthermore, there is an overriding presumption in all such claims that families are assumed to be kosher(Jewish and legitimate) unless, of course, there is strong ground for doubt. This principle is stated in the Talmud (Qiddushin 76b).